Himself



(No Model.) Y

J. W. W-ILBRAHAM.

ATTACHMENT TOILATHES FOR TURNING CRANK PINs.. No. 272,820. atente Feb.'20,1883.,

WITNESSES.

N. PEIERS. Pnclo-ulho npqu. Wnhinmn, D. C.

NITED STATES FFICFZ.

arem HIMSELF, AND THOMAS WILBRAHAM AND OF SAME PLACE.

JAMES VVILBRAHAM, BOTH ATTACHMENT TO LATHES FOR TURNING CRANK PlNS.

SPECIFICATION forming part of Letters Patent No. 272,820, dated February 20, 1883.

Application filed September 11, 1882. (No model.)

To all whom it may concern Be it known that 1, JOHN W. WILBRAHAM, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certainImprovements in Mechanism for Fa cilitating the Turning of Crank- Pins, of which thefollowing is a specification.

My invention consists of certain attachments fora metal-turning lathe for the turning of the pins of crank-shafts, the object of my invention being the steady retention of the crank-shaft in the lathe while its pin is being turned. In the accompanying drawings, Figure 1 is a front view of a lathe, showing the attachment for turning the pins of crank-shafts; Fig. 2, a transverse section of Fig. 1; Figs. 3 and 4, detached perspective views of parts of the device, and Fig. 5 a View illustrating a modification of part ofmy invention.

To the bed A of the lathe is secured the usual head-stock, B, to hearings in which is adapted the spindle a, carrying the cone-pulley E and face-plate D. In place of the usual following head-stock, I secure to the bed of the lathe a frame, F, having an annular recess, 1), in which the disk G fits snugly, but so as to turn freely. On the disk G is a tubular projection or socket, d, and through the latter and the disk passes one straight portion of the crank-shaft W, the pin a: of which has to be turned, the shaft being secured in its place by set-screws passing through the socket. The end of the other straight portion of the crankshaft is fitted into and secured to a socket, e, on a disk or plate H, attached to the faceplate D. The center of the disk is in a dotted line, y, which is a continuation of the axis ofthe lathe spindle, and the distance from this line to the center of the socket d and that of the socket eis equal to the distance from the center of the shaft to the center of its crankln. p Un the bed-plate is the carriage I, to guides on which is adapted a slide-rest, J, the carriage and slide being combined with traversing mechanism similar to that on ordinary slide-lathes, and hence requiring'no description.

A tool-holder, K, projects from and isfirmly 5o secured to the slide-rest, and to this holder is secured the tool m, by which the pin 00 of the crank is turned as the crank is carried round and as the disk G revolves in its hearing.

In turning the crank-pin of a crank-shaft 5 of the character shown in the drawings, it has been usual to secure to the straight portions of the shaft arms having centering-orifices at a distance from the center of the shaft equal to the distance of the center of the crank-pin from that of the shaft, and to adapt the centering-orifices of these arms, that of one arm to the center of the fixed head-stock and that of the other arm to the center of the other head-stock of an ordinary lathe. By this ar- 6 rangement sufficient steadiness and freedom from jars could not be obtained to permit the tool to make a moderately deep and clean cut, and, moreover, the longitudinal compression of the arms between the head-stocks tended to interfere with the truth of the shaft, and thus prevent the accurate turning of the crank-pin.

In my improvement, however, the steady chucking of the crank-shaft to the lathe is assured by securing the shaft at one side of the crank to the socket of theplate H, and at the opposite side to the socket ot' the disk G, the support for theshaft in this disk being brought much nearer to the crank, and consequently nearer to the point where the cutting takes place, than can be done when the shaft is hung by and between the centers of two head-stocks. The straight portions of the shaft may be turned before it is applied to the socket e on the plate H, and to the socket d on the disk 8 G, these sockets being bored to suit the shaft, so that the truth of the crank pin, when turned in respect to the shaft, will be assured.

I propose to provide the plate H with two or more sockets, so that the attachment can be used for turning the pins of cranks of different lengths. Thus, in the present instance a there is an additional socket h on the plate H and a corresponding additional socket, It, on the disk Gr, both these sockets being slightly 5 nearer to the axis of the lathe than those previously referred to, these sockets h h being broughtinto use when the pin or a crank shorterasao er than that on the shaft W has to be turned, and being adapted forthe reception of weights to counterbalance the weight of the crankshaft, and insure steadiness in the running of the lathe.

The frame F is preferably made of two parts, as shown in Fig. 4, and this will be necessary if the annular recess 1) is undercut for the reception of a rib on the disk, as shown in Fig. 5. As the disk is confined to its place, however, bythe crank-shaft, this plan of adapting it to the frame is not necessary.

The plate H may take the place of the faceplate D; but I prefer to retain the latter, so

- that the lathe will he in a condition for use on JOHN W. WILBRAHAM.

\Vitnesses:

HARRY DRURY, HENRY HoWsoN, Jr. 

